There is disclosed a conventional vehicle driving device in an electric vehicle according to Patent Document 1, in which the device includes a pair of right and left electric motors, and a mechanical oil pump is provided between the electric motors, so that oil is supplied to an oil passage inside a driving shaft to lubricate a torque transmission system; in addition, a motor for traveling is cooled by an electric oil pump that is provided additionally. The mechanical oil pump defines, with a partition wall of a case and a pump cover, a pump chamber in which a rotator is contained, and rotates by driving the electric motors.